Spencer’s short walk from one E-Ring office to another belied an immense jump in responsibility, from a service secretary in charge of manning and equipping a pair of service branches to a practitioner of global strategy and the second link in the wartime chain of command. How long will he keep the job? No one knows.

It’s the latest move in a bizarre game of musical chairs playing out at the Pentagon, which now has vacancies at 18 top political positions. And that game could continue well into the summer.

“We will not presume confirmation and it is the prerogative of the Senate to take as long as they think is necessary to examine and confirm the nominee,” Eric Chewning, chief of staff to the acting defense secretary, said at an impromptu briefing at the Pentagon on Monday afternoon. “Secretary Spencer is prepared to remain in the role until there is a Senate-confirmed secretary of defense.”

Esper has served since 2017 as Secretary of the Army, a position he did not formally relinquish when he was named Acting Defense Secretary on June 24. His formal nomination means he can no longer serve in an acting capacity, so he is now once more Army secretary.

“Secretary Spencer has the full authority and responsibility of the Secretary of Defense,” Jonathan Hoffman, the Pentagon’s chief spokesman, said in a statement. “The senior team supporting the Office of the Secretary remains in place to ensure institutional continuity.”

At the Pentagon, Esper’s picture at the Pentagon’s River Entrance, the one used by most senior defense officials and foreign dignitaries, has been removed and replaced with a picture of Spencer. But even if Esper’s confirmation moves quickly, Spencer’s picture could remain high on the leadership wall for some time.

That’s because David Norquist, the Pentagon comptroller and CFO, who has also been “performing the duties” of the deputy defense secretary since January, is then expected to receive a formal nomination from Trump to be deputy defense secretary. At that point, Norquist will go back to being comptroller and Spencer will “perform the duties” of the deputy defense secretary.

Assuming the Senate confirms Norquist, Spencer would then go back to being Navy secretary.

But there’s more. The White House has still not formally nominated Barbara Barrett, who Trump, in May, said he would nominate as Air Force secretary. Also, Trump has said he would nominate Ryan McCarthy, the Army undersecretary to replace Esper as Army secretary.

That would mean two more Senate confirmations, one for McCarthy and one for whoever the White House nominates for Army undersecretary.

Then there’s the uniformed side of the house. The Senate last week held a confirmation hearing for Gen. Mark Milley, the Army chief of staff, to become Chairman of the Joint Chiefs of Staff. Also, the nomination of Air Force Gen. John Hyten, head of U.S. Strategic Command, to be Joint Chiefs vice chairman has been in limbo following sexual assault allegations.

Correction: This story originally misstated the position to which Gen. Milley has been nominated.

By Marcus Weisgerber // Marcus Weisgerber is the global business editor for Defense One, where he writes about the intersection of business and national security. He has been covering defense and national security issues for more than a decade, previously as Pentagon correspondent for Defense News and chief editor of Inside the Air Force. He has reported from Afghanistan, the Middle East, Europe, and Asia, and often travels with the defense secretary and other senior military officials.